


Make-Shift Sister

by PrettySami



Category: Shingeki no Kyojin | Attack on Titan
Genre: Crossdressing, M/M, Panties, Shingeki no Crossdressing, Slight OCDness, Stockings, Underage - Freeform
Language: English
Status: Completed
Published: 2014-01-20
Updated: 2014-01-20
Packaged: 2018-01-09 10:18:39
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings, Underage
Chapters: 1
Words: 3,038
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1144804
Author URL: https://archiveofourown.org/users/PrettySami/pseuds/PrettySami
Summary: <blockquote class="userstuff">
              <p>Or that one fic where Mikasa wants a sister and decides that Armin will suffice.</p>
            </blockquote>





	Make-Shift Sister

**Author's Note:**

  * For [jenovasilver](https://archiveofourown.org/users/jenovasilver/gifts).



> No excuse for this except that I’m a perv and so is Jenos. Hey! At least it’s consensual Eren/Armin this time! :D  
> Here, have some companion art (both are sorta NSFW): [(♥)](http://pr3ttysami.tumblr.com/post/71783821747/headcanon-mikasa-loves-eren-and-everything-but) [(♥)](http://pr3ttysami.tumblr.com/post/71459652262/finally-figured-out-how-to-draw-this-little)

Armin sat as still as he could as Mikasa’s tiny fingers brushed his hair into twin tails. They’d always play this way when the doctor was away and her adoptive mother was too busy with extra chores. She’d send them to amuse themselves saying they were only underfoot if they offered to lend a hand (this being directed mainly at her green-eyed rascal of a son). Mikasa herself loved playing with Eren but often grew tired of his repetitive games which all seemed to involve varying degrees of roughhousing. There also weren’t many girls their age in the neighborhood so Mikasa had decided to make due. 

It had started slowly since she wasn’t very talkative. But sweet little Armin was always open to chat with (or _to_ as the case may be) Mikasa. When she was bored enough to let Eren wander out of her sight Armin would chat her up about any subject and she would occasionally respond in her quiet voice. During one such semi-one-sided conversation Armin confided, “I want to go outside the Walls more than anything. Is there something you want very much, Mikasa?”

The raven-haired girl didn’t reply right away. Instead she looked into the blue pools of her friend’s eyes, at his shoulder-length blonde hair, small frame and replied with what sounded like a sense of realization, “A sister…”

Armin smiled in an understanding sort of way. “Oh…yeah it must be hard hanging around boys all the time. I guess it’s like Eren and I are your brothers, huh?”

“You’ll do,” she replied unblinkingly. Armin looked confused but Mikasa didn’t elaborate. She got up from the step they were sitting on and went inside the house. The little blonde followed her, curiosity getting the better of him. She walked back to her and Eren’s shared room and pulled out a plethora of hair ribbons. She’d gestured for Armin to sit and he’d done so. She then braided his hair the way she’d seem some older girls do and added the ribbons wherever her ten year old fingers fancied. 

When she was done she stood back to admire her work. Armin patted his hair gingerly, not wanting to ruin what she’d done. And since he couldn’t see it he looked over his shoulder at Mikasa and asked jokingly, “How do I look?”

A tiny smile graced her features as she replied honestly, “Pretty.”

Armin was pulled from his reprieve by Mikasa breathing, “Done.” He reached up to touch the new twin tails and smiled. She’d gotten much better at this over the past few months.

“Can we go to the Doctor’s room so I can see?” Armin was close to giggling. They’d always hurry off to the one mirror in the house so he could get a look at himself.

“Not yet,” Mikasa moved from behind him and went to her wardrobe. Before she opened it she gave Armin a look like she was deciding something. He returned her stare with wide-eyed silence. She opened her wardrobe then and tugged out a simple blue dress and a matching apron. She tossed them onto her bed and walked up to Armin reaching for the buttons on his shirt. And Armin, too young to be terribly shy, let her. His cardigan dropped to the floor along with his cotton linen shirt. Mikasa popped the button of his shorts and undid the fly. Armin stepped out of them and stood in his plain cotton underwear as she helped him put on the dress, not wanting to mess his hair. Next came the apron. It was lace covered and more decorative than functional as was typical for an apron for a young girl.

Mikasa spent a moment or two adjusting this and fluffing that before taking a single step back to scrutinize the blonde. Armin felt his cheeks warm under her gaze but couldn’t quite figure out why… She took his hand abruptly and half-dragged him to her “parent’s” room, stopping in front of the big full-length mirror. Armin couldn’t believe his eyes. He leaned forward and extended a trembling hand toward his reflection. “I…” His voice died unexpectedly. Mikasa smiled her soft smile in agreement. 

Eren burst into the house as he normally did around this time shouting his arrival. When no one replied (not even Mikasa) he walked about the house poking his head in each room until he found her and-

“Who is this?” Eren wasn’t pleased there was a stranger in his parent’s room, even if this stranger was particularly pretty. 

“Eren,” said the pretty girl. “It’s me, it’s-“ The brunette took a step closer, eyes widening as he recognized his best friend’s voice.

“Armin? But why are you dressed like…?” Eren grasped the thin material of the apron between inquisitive fingers. He rested his hands on the blonde’s hips and turned him around so he could tug on the large ornate bow. Then, with absolutely no preamble he lifted the back of the dress, earning a yelp from Armin. “You look petty like this.” Eren said. 

The game was played many more times with the somewhat limited selection of Mikasa’s dresses. Most times Eren would come and see the end result, poking and prodding his friend, making Armin squeal. Other times they’d play the quiet games Mikasa wanted to play: they’d pretend to have tea or play house (Armin was always the ‘daughter’ since he was shorter than her.) It was the game he missed most after the Fall of the Wall.

\--Present Day--

_Another_ scouting mission gone completely awry within the confines of what remained of the interior of Wall Maria. So much so, that somehow Eren and Armin had become completely separated from their respective groups. Both were out of flares but luckily for them it was nightfall and they decided to duck into one of the abandoned houses until morning then seek out their superiors. Armin picked a medium-sized farmhouse that hadn’t taken much abuse if any “probably due to it being so far out.” He’d concluded.

Eren broke the lock and they ventured inside cautiously. “They had time to lock the door?” he wondered aloud.

“And time to grab other things too it looks like,” Armin gestured to cabinets that stood open, empty stretches of wall where portraits once hung, select books from shelves had been removed leaving gaps here and there. 

“For farmers they had a lot of stuff…” Eren commented, proceeding down a long hall, blades first. 

“Probably heirlooms,” Armin said more to himself than to Eren. He scanned the shelves thoughtfully then set about removing his 3DMG. There was clearly no one here and Titans wouldn’t attack at night. _Since the house is on fire we may as well warm ourselves,_ he thought and went to go pick out a bedroom (the house was large enough to have many). He laid his things in the first room he found lighting a candle with some matches he had.

“Armin,” Eren called from one of the other rooms. “Come look what I found!” He didn’t sound scared or hurt so the blonde took his time. Eren had gone deeper into the house and into a slightly smaller room. A lantern stood glowing on an old worn dresser as well as one in the bracket on the wall. It looked to have been the room of a teenage girl given the little vanity table and the tall wardrobe in the corner. It stood open and Eren was beside it holding something blue and poofy. He held it up suddenly grinning like an idiot, “Look! It’s a dress!”

Armin smiled. “I can see that, what do you intend-?” Eren stepped closer and raised an eyebrow. “Really, Eren? We aren’t kids anymore, I couldn’t-!”

“Sure you could.” The brunette’s features turned to pleading. “I bet you’d look even prettier now.”

Armin wasn’t even sure how to take that but he blushed anyway. Was Eren being serious? It had been years since they’d played this game. It wasn’t that he hadn’t wanted too but with all that had been going on since the fall of the Wall there was really no time. Not to mention resources.

“C’mon Armin,” Eren nearly whined. “For old time’s sake?”

Armin sighed and rolled his eyes. “I guess it can’t hurt anything…” Eren cheered handing the garment to his friend and sat down on the bed next to his own discarded 3DMG (he seemed to have shaken the dust out of the old comforter earlier.) Armin swallowed and sat the dress next to his friend. “Are you just going to watch?”

Eren nodded and smiled. A nervous giggle rose from Armin’s throat. Ok then. He wasn’t sure where to start really. Mikasa had always helped him, she always started with his hair…

“What’s wrong?” Eren asked, noting Armin’s hesitation.

“It’s just Mikasa would always do my hair first…”

“Maybe you should start there then?”

“I can’t, I mean she,” Armin stammered and Eren seemed to understand. He stood and approached Armin from behind. He separated blonde strands and made a pair of passable braided twin tails. He borrowed some of the girls’ ribbons from a drawer in the vanity to secure them. 

Eren tugged them in a teasingly and Armin batted him away with a laugh. “Now what?” Eren came around and gestured at the mirror. “Wanna see how it looks?”

“No, we always looked at the end, after I had everything on!” Armin admonished. All that was really left was the dress but Eren started digging through the drawers of the dresser. He pulled out a pair of soft sheer stockings as well as a pair of cream colored panties. “Eren!” Armin almost screamed.

“What?” Eren asked unashamedly. “They’re in the drawer! They’re clean.” That wasn’t the point but Armin couldn’t bring himself to explain. “So what next?”

“Uhm…” Armin recovered a little. “Well she always helped me get dressed so I didn’t mess up my hair. Mikasa would undress me…” Now that Armin was older and looking back on this a very different feeling was coiling in his belly. Not that he’d been attracted to Mikasa, nor she him for that matter. It was just that the implications of her removing his clothes… He jerked at the feel of Eren helping him out of his jacket. He looked up into the turquoise eyes. Eren didn’t work especially quickly and he undid each button of Armin’s shirt as if savoring it. When it was open he slid his hands in and around the blonde. 

Armin gasped at the feeling of calloused fingers on his warm flesh. He opened his mouth to say something but stopped when Eren pulled the shirt off. He kneeled and helped Armin out of his boots. He remained on his knees and lifted his hands to open Armin’s fly. He looked up briefly and Armin’s breath caught in his throat, his blush spreading to his exposed chest. A tiny whimper escaped him as in one movement Eren slipped off his pants and boxer briefs.

He could feel Eren’s breath on his skin and his cock twitched hopefully, already making its way to half-mast. The brunette retrieved the panties from the bed and held them open for Armin to step into. He did so tentatively and Eren slid the slippery fabric up his legs. He didn’t even try to tuck his besty’s need into the garment; he simply kissed the still-exposed inches making the blonde squirm and moan. Eren lapped unabashedly at the blonde through the material. The thin scrap of fabric was quickly soaked and Armin had to lean forward and rest his hands on the brunette’s head to keep himself from toppling over. The larger boy’s hands gripped pale thighs, squeezing intermittently. Eren turned his busy mouth to the inside of Armin’s thigh and he cried out suddenly. Pressure had built in his lower belly and he couldn’t help the strained groan of “Eren,”

The brunette sucked a mark into the already slightly bruised thigh and came away with a ‘pop’. Eren turned Armin so that the backs of his knees tapped the bed forcing him to sit. The stockings came next and finding no garters Eren muttered, “Oh well, won’t be on long anyway…” Armin gulped nervously as his legs were maneuvered into the sheer fabric. Eren paused here and there to kiss or lick some part of him. Armin only realized he’d been lying down when Eren helps him to his feet and then to the mirror.

Armin can’t help the startled, “Oh!” when he sees himself. He takes in the way the way the bodice hugs his slim yet muscular figure, the was the dress flares out just slightly making it look like he might have girlish hips, and his stockinged ankles and feet are just visible. He marvels for a few seconds more before he registers that his reflection isn’t alone. Eren had stepped up behind him and was smiling wryly. “How’d I do? Just as good as Mikasa, hm?”

“Oh Eren this is …thank you. This is it. We’d usually play a game or something-“ He’s silenced abruptly as Eren’s hands travel up his sides.

“That’s it? I think you’re forgetting a part.” Eren nosed at the exposed flesh on the back of Armin’s neck making the smaller boy gasp. “The part when I would come in and inspect her work.”

“O-oh?” Armin couldn’t help but huff out a laugh as he leaned back into his friend’s touch. “Is that what you call it?”

“Mm-hmm,” came the muffled reply and Eren rested his chin on Armin’s shoulder. He brought a hand up and crossed his arm in front of Armin’s throat and across his shoulders. With his free hand he rucked up the back of the dress and dragged his hand around to grip the shorter boy’s straining member. Armin stared at his reflection as Eren caressed and fondled him under the dress. Even through the layers of fabric he could feel Eren’s dick pressing into his backside, hot and hard. His knees grew weak and if it weren’t for Eren’s strong arm across him he would’ve fallen onto the dusty floor. Eren stroked him roughly and Armin was close to screaming. 

“Eren, wait stop!” He sobbed not wanting to come so quickly. “I’m gonna come please stop!”

Eren did stop then but only to push his friend back onto the bed. Armin’s limbs were adjusted so that his legs were open. The brunette held up the hem of the dress and Armin felt strangely embarrassed. He bunched the fabric around his hips and when Armin moved to pull the panties off Eren placed a hand on his. “Leave them on.”

Armin felt his body heat up as he watched Eren grab the mineral oil they used on their maneuver gear from a pouch on his discarded belt. He then hastily rid himself of his pants and poured a bit of the slippery liquid into his palm. He recorked the bottle and tossed it aside as he knelt between Armin’s legs. He gazed down with a look his friend had never seen before. Lust. 

Slowly, Eren reached down and tugged Armin’s panties to the side and poured the oil into him. He slid a confident finger into his friend and watched his back arch at the intrusion. The layers of the dress obscured Armin’s view but he felt it when a second finger joined the first, twisting and working its’ way ever deeper bringing tears to Armin’s eyes and unfettered moans to his lips.

All too soon it seemed like Eren couldn’t take much more and he used the remaining oil to slick his drooling cock. He hitched a hand under the Armin’s knee and brought it over his shoulder. He then proceeded to slide himself in a carefully as he could. He breathed out a relieved sigh and Armin tried to adjust beneath him. Eren took a moment then to get a really good look at Armin in all of his “finery”. The skirts were pushed up far enough that his belly was partially exposed and over the layers of lace and tulle he could see his friend’s flushed face. One gorgeous blue eye squeezed shut. Pink lips parted as he tried to steady his breaths. There was really no one Eren had ever wanted more than Armin. He started a slow, gentle pace and didn’t bother holding back a surprised grunt when he bumped the bundle of nerves that was Armin’s prostate.

Armin seemed to be beyond words, opting for unintelligible fuck-babble instead of trying to string entire sentences together. He could feel himself coming abort beneath his Eren as he seated himself fully over and over again. Armin couldn’t believe how close he was and so soon! He tried to give himself some credit, after all this was so much more than a mere makeout session. 

Eren rolled his hips once more and allowed his climax to claim him. The shorter boy could feel Eren filling him up even as he continued to thrust, the sloshing sound obscene in the silence of the abandoned house. Armin came with a sob; sticky white ropes spilled over the crushed fabric. He heard the embarrassing sound of Eren pulling out of his abused hole but couldn’t be assed to blush at this point.

“Was it…was it good?” Eren panted and he flopped down beside the blonde and turned to nuzzle his cheek.

“Yeah,” Armin said with a nod.

“Best you ever had?”

“Only.”

“Huh?” Green eyes made contact with blue ones. “Really?”

“Well, yeah.” Armin frowned confusedly. “Aren’t I…?” It was easy to tell from Eren’s expression that he _wasn’t_. “Who?” he asked with more curiosity than jealousy.

“Uh…Marco.” Eren said sheepishly. “But it was before him and Jean were going out!” he blurted.

“Oh, I’m gonna tell on you!” Armin giggled.

“The hell you are!” The two alternated between wrestling and making out, taking time to just enjoy each other’s company before Armin sat up suddenly.

“What was that?”

“What was wh-?”

“Oi, are you shitty brats in here or what?” came Levi’s irritated voice from the front door.

Oh shit.


End file.
